The present invention relates to bicycle frames, and particularly to weld joints of tubular bicycle frames.
Bicycle frames are commonly manufactured from tubes that are coupled together into a desired configuration. When the tubes are metal (e.g., steel, aluminum, titanium, etc.), they can be welded together to form the bicycle frame. When manufacturing a welded bicycle frame, the ends of the tubes are pre-cut so that the tubes fit together to form pre-weld joints between the tubes. For example, one tube can be mitered so that it wraps snugly around the tube to which it will be welded. When tubes of similar size are coupled using a mitered joint, the geometry of the joint varies dramatically around the tube interface, from essentially a T-joint at the top and bottom to essentially a tangent joint on the sides, with the mitered tube having a razor thin wall thickness at the tangent joint.
When welding tubes having mitered joints, a weld fillet is formed around the joint. Due to the varying joint geometry of the above-described mitered joint, creating a good, consistent weld is very difficult. At the location where the tubes are tangent, the weld bead commonly protrudes substantially above the surfaces of the tubes being welded. If a smooth joint is desired, one would need to grind or sand the weld bead.